php - mysql - php blob 字段？

Question

我有一个查询返回的结果似乎是一个 BLOB

SELECT CAST(GROUP_CONCAT(CONCAT(value,'(',qty,')') SEPARATOR ', ') AS CHAR)a 
FROM ( 
   SELECT value,count(*) qty 
     FROM extra_field_values 
    WHERE fieldid = @fieldid 
      AND value != '' 
      AND itemid IN (7,8,10,12,15,16,17,18,19,20,21,22,23,24,25,26) 
   GROUP BY value
) x 

表格是

CREATE TABLE `extra_field_values` (
   `itemid` int(11) NOT NULL DEFAULT '0',
   `fieldid` int(11) NOT NULL DEFAULT '0',
   `value` text NOT NULL,
   KEY `itemid` (`itemid`),
   KEY `fieldid` (`fieldid`),
   KEY `value` (`value`(1)),
   KEY `inx` (`itemid`,`fieldid`,`value`(1))
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

主要思想是我希望每行返回一个字符串:::count 由### 分隔。

问题是 php 返回空结果。就驱动程序而言，我已经尝试过 mysql 和 mysqli。 有什么想法吗？

PHP

$result = $mysqli->query("    SELECT CAST(GROUP_CONCAT(CONCAT(value,'(',qty,')') SEPARATOR ', ') AS CHAR)a 
FROM ( 
   SELECT value,count(*) qty 
     FROM extra_field_values 
    WHERE fieldid = @fieldid 
      AND value != '' 
      AND itemid IN (7,8,10,12,15,16,17,18,19,20,21,22,23,24,25,26) 
   GROUP BY value
) x ") ;
    while( $row = $result->fetch_assoc() ){ 
        print_r($row);
    }

即使您通过 phpmyadmin 执行它，它也会返回 null。在 EMS mysql 上试用它，效果非常好。

完整查询

SELECT 
extra_field_values.fieldid,
extra_fields.var_name,
extra_fields.field,
extra_fields.type,
@fieldid:=extra_field_values.fieldid, 
( 
 SELECT CAST(GROUP_CONCAT(CONCAT(value,'(',qty,')') SEPARATOR ', ') AS CHAR) a 
 FROM ( SELECT value, @fieldid, count(*) qty FROM extra_field_values WHERE fieldid = @fieldid GROUP BY value ) x 
) as v,
count(itemid) as total,
(SELECT groupid FROM extra_fields_groups_items WHERE itemid = @fieldid) as groupid 
FROM extra_field_values INNER JOIN extra_fields 
  ON (extra_field_values.fieldid=extra_fields.fieldid) 
WHERE module = 'listings' 
 AND itemid IN (7,8,10,12,15,16,17,18,19,20,21,22,23,24,25,26) 
 AND settings LIKE '%"search";s:1:"1"%' 
GROUP BY fieldid

Answer 1

您正在查询与 session 变量 @fieldid 匹配的字段，但我猜您没有在 mysqli session 或 phpmyadmin 环境中定义该变量。

SET @fieldid := 1234;
SELECT ... WHERE fieldid = @fieldid ...

否则您可以使用 ? 作为 fieldid 的查询参数占位符并将其绑定(bind)到 PHP 变量。

参见 http://php.net/manual/en/mysqli-stmt.bind-param.php

---

在不使用@fieldid session 变量的情况下，以下查询是否执行您想要的操作？

SELECT x.fieldid, x.var_name, x.field, x.type, x.groupid, COUNT(*) AS total,
  CAST(GROUP_CONCAT(CONCAT(x.value,'(',x.qty,')') SEPARATOR ', ') AS CHAR) a 
FROM ( 
  SELECT v.value, v.fieldid, f.var_name, f.field, f.type, g.groupid, COUNT(*) AS qty 
  FROM extra_field_values AS v
  INNER JOIN extra_fields AS f ON f.fieldid=v.fieldid
  INNER JOIN extra_fields_groups_item AS g ON g.itemid=v.fieldid
  WHERE f.module = 'listings'
   AND f.itemid IN (7,8,10,12,15,16,17,18,19,20,21,22,23,24,25,26) 
   AND f.settings LIKE '%"search";s:1:"1"%' 
  GROUP BY v.value, v.fieldid
  ) as x
GROUP BY x.fieldid